1. Field of the Invention
The present invention relates to a webbing retractor for taking up an occupant-restraining webbing used in a seat belt apparatus for a vehicle.
2. Description of the Related Art
A webbing retractor for taking up an occupant-restraining webbing onto a takeup shaft in the form of a roll is so designed as to allow the occupant to pull out the webbing out of the webbing retractor so as to cause the webbing to be applied around the occupant.
A webbing retractor has been proposed which is so arranged that, at the time of a sudden deceleration of a vehicle, the rotation of the takeup shaft in a webbing pulling-out direction is prevented by a takeup-shaft locking mechanism, and a clamping means is actuated to clamp and lock an intermediate portion of the webbing so that a tensile force will not act on the portion of the webbing wound around the takeup shaft, thereby preventing the tight winding of the webbing (Japanese Patent Application Laid-Open No. 61-205532).
With such a webbing retractor, however, since the webbing may become damaged if a clamping force exceeding a predetermined level is applied to the webbing by the clamping means, the webbing needs to be reinforced further, or a complicated clamped-state canceling mechanism must be provided for restricting a webbing-clamping force so that a load more than is necessary will not act on the portion of the webbing being clamped.